Solar cells are expected as new energy sources owing to their capability of directly converting clean and inexhaustibly-supplied sunlight into electricity. In general, the output power per solar cell is several watts. Accordingly, for use of such a solar cell as a power source (energy source) for a house, a building, or the like, a solar cell module is used which is capable of providing higher output power by use of a plurality of solar cells electrically connected to each other.
In this respect, a so-called back junction solar cell has been proposed in which a plurality of n-side fine-line electrodes and a plurality of p-side fine-line electrodes are alternately formed on a back surface of a semiconductor substrate for the purpose of enlarging a light receiving area (see Japanese Patent Application Publication No. 2005-11869). The plurality of n-side fine-line electrodes are connected to an n-side connecting electrode formed on one end portion of the semiconductor substrate. The plurality of p-side fine-line electrodes are connected to a p-side connecting electrode formed on the opposite end portion of the semiconductor substrate. One solar cell and another solar cell next to the one solar cell are electrically connected in series with the n-side connecting electrode of the one solar cell and the p-side connecting electrode of the next solar cell connected to each other through a wiring member.
In a case where a semiconductor substrate is of a first conductivity type, however, the connecting electrode of the first conductivity type has a problem of poor efficiency of collecting majority carriers.
Specifically, in a solar cell including an n-type semiconductor substrate, for example, many of holes (minority carriers) generated around the n-side connecting electrode are recombined with electrons (majority carriers) before being diffused into the p-side fine-line electrodes. As a result, the number of electrons collected by the n-side connecting electrode is reduced.
Since the first conductivity side connecting electrode cannot efficiently collect carriers as described above, incident light falling on a region of the light receiving surface on an opposite side to the first conductivity side connecting electrode cannot utilized effectively.
The present invention has been made in consideration of the above problem, and an objective thereof is to provide a solar cell module including solar cells capable of effective use of incident light, a solar cell and a solar cell module manufacturing method.